We have one, or two of our americanas that have been laying a soft shelled egg for a week. I have not seen it happen, we have 3 americanas. One of them has been laying as normal, she has a big egg, so we know who that is. But, either two are laying the soft shells, or one stopped laying. They are about 10 months old, and did great all winter with the exception of one soft shelled egg about a month ago. Yesterday, we got a very thin shell. These have all been in the coop, not the nest box. I added some ACv to the water the last few days, they are on layer pellets, they get yogurt, eggs, shells, kitchen scraps, some scratch. No sign of worms or mites. All other chickens in the coop have had normal laying. Should I be concerned, should I try anything else, or is this just a cycle? Oh, they also get to free range a few days a week, and there is oyster shell available to them.